Image Forming Apparatus Transfer Voltage Adjustment
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Solution Overview
Problem
In image forming apparatuses with double-sided printing functions, the precision of setting transfer conditions on the second side is reduced due to the influence of the toner image formed on the first side, leading to variations in toner transferred mass per unit area and density differences between overlapping and non-overlapping areas of test patterns.
Innovation Solution
The apparatus forms a test chart with first and second test images on the first and second sides, respectively, where the second test images are created after forming predetermined toner images under the same conditions on the first side to overlap with the areas where the second test images are formed, ensuring consistent toner transferred mass per unit area and precise transfer condition setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If test patterns are formed on both front and back sides of recording material with different transfer conditions, then transfer condition adjustment is enabled, but the toner image on the front side creates electrical resistance that causes voltage changes and density variations in the back side test pattern
Solution Approach 1:
The patent divides the test pattern on the back side into multiple density regions (first through fourth density regions with different toner concentrations). By segmenting the test pattern into regions with progressively higher toner densities, the system can identify which region provides stable density measurements that are not affected by the electrical resistance from the front side toner image, thus resolving the measurement precision issue while maintaining the dual-side adjustment capability
Solution Approach 2:
The patent applies different transfer conditions to different regions of the test pattern on the back side. Specifically, the fourth density region (with highest toner concentration) is used for transfer condition adjustment because its density is least affected by the front side's electrical resistance. This local quality approach allows the system to use specific regions for specific purposes: some regions for accurate measurement, others for testing different transfer conditions
2Manufacturing precision
If patch images with different transfer conditions are printed to create test pattern, then transfer current optimization is enabled, but the toner transferred mass per unit area varies causing electrical resistance changes that affect subsequent back side printing
Solution Approach 1:
The patent performs preliminary transfer condition optimization on the front side using patch images with different transfer currents. By pre-determining the optimal transfer conditions on the front side, the system establishes a baseline that allows the back side test pattern to be formed under controlled conditions. The fourth density region on the back side is specifically designed to be formed under these pre-optimized conditions, ensuring consistent toner transferred mass that is not affected by front side variations
Solution Approach 2:
The patent systematically changes transfer current parameters when forming patch images on the front side to determine optimal transfer conditions. By varying the transfer current parameter across different patch images and observing the resulting toner transferred mass, the system identifies the parameter settings that produce consistent, stable toner transfer. These optimized parameters are then applied to the back side test pattern formation, ensuring that the fourth density region has consistent toner transferred mass per unit area
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach maintains high precision in setting transfer conditions on the second side while ensuring transferability, even when a toner image is formed on the first side, by keeping the toner transferred mass per unit area consistent and reducing density variations, thus enhancing image quality.
Implementation Method 1
a transfer device configured to transfer the toner image borne on the image bearing member to a recording material
Data Source
AI summary
An image forming apparatus includes a controller configured to control a first and a second voltage applied to a transfer device when transferring an image to a first and a second side of a recording material, respectively. The controller controls a mode that outputs a test chart on which at least one of a plurality of first test images for adjusting the first voltage and a plurality of second test images for adjusting the second voltage is formed. In a case of forming the second test images on a second side of the test chart, and before forming the second test images, the controller forms a plurality of predetermined toner images under a same image forming condition on a first side of the test chart so that the predetermined toner images are formed on a plurality of predetermined areas overlapping each area where the second test images are to be formed.